The present invention relates to a casing material based on cellulose which is resistant to mold fungus, to a process for its manufacture and to a fungicidal agent for cellulose sausage casings.
It is known to store foodstuff casings, in particular shirred sausage casings, so-called shirred sticks, of cellulose at a high moisture content before processing. The moisture content is usually more than 20% by weight, relative to the casing, and enables the casings to be processed without prior soaking in water. Disadvantageously, however, the growth of undesired mold fungus and other microorganisms on the cellulose casing is greatly accelerated when the casings are stored under these conditions before processing. The risk of undesired mold formation on the casing surface also still exists even when the casing, filled with a foodstuff as intended, is stored.
Air-cured, long-keeping and uncooked sausages are frequently produced by the natural maturing process. In this process, the sausages, after smoking, are dried in air for a prolonged period of time in order to give them longkeeping qualities. The water vapor escapes outwardly from the sausage meat through the casing wall. If ventilation is poor, undesired mold formation occurs in this case due to the high moisture content on the outside of the casing.
Other types of sausage, such as, for example, types of liver sausage, are frequently packaged in plastic bags. In this case also, undesired mold growth can cause spoiling of the sausage.
To prevent the growth of mold fungus on cellulose casings, ascorbic acid and sorbic acid and their salts have, for example, been described as fungicidal agents, the casing material being impregnated with aqueous solutions of these substances (U.S. Pat. No. 979,410). These known agents are, however, less suitable for casings which must be soaked in water or boiled during processing, since the agents dissolve in water and are thereby quantitatively detached from the casing material. Moreover, there is a risk of the substances exerting an impermissible preserving action on the packaged foodstuff. Also for reasons of foodstuff law, a number of fungicidal compounds are not permitted in packaging material for foodstuffs.
Furthermore, the antimicrobial action of glycerol monolaurate has been known for a long time. According to U.S. Pat. No. 4,002,775, this compound is to be used in medicine, in the preparation of medicaments and cosmetics, and in the preservation of foodstuffs. Even though the problem of mold infestation of sausage casings has been known for a long time and intensive searches for a solution to the problem have been made, as proven by a large number of publications, this compound has so far escaped attention.